1:5 detail of drain 26 on Athol Road. One of the older drains in the area, most likely placed into the road when the street was first built. I found the layers and fragments of past road surfaces surrounding the drain interesting, observing the different materials chosen at different times which also tells you different methods that would have been used to set down the material. Smooth slates of stone would have been individually laid out in a pattern to encircle the punched out hole of the drain. Later, tarmac has been poured to fill in pot holes and break aways from use and weathering. Now, the drain sits framed with only pieces of its original surrounds and has become a micro flower bed for grasses and moss.
Circular drains were used as they used less material than rectangular ones and also could not fall into the drain. At the center the shape is for the cover key which would be inserted and twisted to help lift the drain cover out place.